The present invention disclosed herein relates to the field of portable bag closing sewing machines and comprises an improved portable machine with a highly reliable self-oiling system which provides essential lubrication for the machine and requires minimal attention by an operator.
Many manufacturing facilities produce products which are granular, fibrous, or are in other ways suitable for storage in bags or sacks and require packaging machinery able to stitch closed the top of such open-topped bags or sacks. In many packaging applications it is desirable to use small, hand-held, portable bag-closing sewing machines like that disclosed in U.S. Pat. No. 3,094,955, and such machines are particularly necessary in packaging situations where the sack or bag flow is not continuous or where large and heavy stationary machines and moving conveyor belts are not practical or available. Such portable machines, to be practical and commercially accepted, must be lightweight, easy to handle, highly reliable, resistant to jamming or failure, simple to operate, and easy to lubricate.
Regular lubrication of these portable bag-closing sewing machines is essential since such machines are commonly utilized in packaging products which are dusty and abrasive, such as powders, fertilizers, mineral products, foods, and the like. In some applications such portable machines may see almost round-the-clock duty in assembly line or shipping dock environments and they commonly are subjected to heavy use in dusty and abrasive environments abusive to mechanical movements, making regular lubrication critical to uninterrupted operation.
The requirement of regular lubrication has been recognized and provided in the field of larger, heavier, stationary bag-closing machines where the weight and complexity of an added self-lubrication system do not pose a problem to commercial acceptance. For example, U.S. Pat. No. 3,478,709 discloses a stationary bag-closing machine with a highly efficient internal lubrication system utilizing a series of tubes, manifolds and a continuous duty pump to move oil to all interval parts of a sealed sewing machine unit. Despite the need for a self-lubricated portable bag-closing sewing machine, prior to the present invention no portable machine had been successfully equipped with a self-lubricating system which was sufficiently lightweight, simple and reliable as to be commercially acceptable. Prior to the present invention, portable bag-closing machines were lubricated by means of either disassembling the housing of the machine to dispense oil or lubricant on appropriate moving parts or, alternatively, lubricating the components through approximately a dozen or more external nipples or oiling locations. While existing machines without self-lubrication features function extremely well and provide long life when given proper care, it has been found that for various reasons, many of the machines do not receive required lubrication and go untended until the machine fails.
Because operation of most portable bag-closing machines is a simple, easily understood task, operation is commonly assigned to unskilled, newly-hired employees who often do not appreciate the importance of regular oiling of the portable machine. Consequently, a machine which might otherwise last for years often fails prematurely because of the abrasive environment in which it functions and the sometimes total lack of oiling and lubrication.
It is thus desirable to provide a portable bag-closing sewing machine which is capable of self-lubrication from a simple oil reservoir, which does not become unnecessarily complex or expensive, which does not require extensive internal tubing or added pumping devices which add significant weight or bulk to the machine. The present invention accomplishes these goals.